The Pineal Gland

Tumors of the pineal region represent approximately 1% of all brain tumors and 3–10% of pediatric brain tumors. A variety of tumors may involve this region, reflecting the complex histology and anatomy of the pineal gland. Tumors from the intrinsic pineocytes, designated pineal parenchymal tumors, show a spectrum of differentiation from the well-differentiated pineocytoma to the highly malignant, primitive pineoblastoma. The papillary tumor of the pineal region (PTPR) is a rare neuroepithelial tumor believed to arise from specialized ependymal cells of the subcommisural organ. Gliomas, particularly astrocytomas, may arise from the supporting glial cells. Meningiomas and other mesenchymal tumors may originate from the meningeal coverings of the pineal or from the falx or tentorium. Lastly, a large proportion of tumors involving this region, accounting for almost 50% of pineal malignancies, are germ cell tumors, with germinomas being the most common of these neoplasms.